The first section of this Mazurka comprises of a parallel period. This period, serving a expositional function, consists of two phrases of asymmetric length. The first phrase, 4 measures long, ends on an IAC, providing an elision into the next phrase. The second phrase of unequal length, presents new material, finishing on a half cadence 8 measures later. The second period is nearly identical, thus it is still considered to have an expositional function. The last few measures of the last phrase draw out the end, creating a cadential extension that resolves to a PAC.
In the second section there is a change of character. The keyboard drops down to piano, and the melodic motion slows. Although Chopin keeps his dotted rhythms and repeated bass. The first 8 measures represents the first phrase of the of the phrase group. As it is new material, it is an exposition. It looks like this phrase might end on an authentic cadence, I'm not too sure. Notice the brief borrowed major tonic chord. The next 16 measures, in my opinion, are transitional. There are no consequent phrases to the new melodic material presented in this period, and these 2 asymmetrical phrases play with modulation, chromaticism and dynamics eliding into the final section.
This last section is practically identical to the first period, merely restating the music played in the A section. There is a cadential extension in the very end leading to a HC, then to a termitive function.
Although I liked this piece, much as I like all of Chopin's works, I found it hard to analyze. The more I thought about what a section/phrase/function could be, the more questions and options I found. One might explore the second section more. There will probably be arguments that this period is actually developmental.